This invention relates generally to the field of materials construction and, more specifically, to a method and system for constructing a structural foam part.
Many industries, such as the aerospace, aircraft, ship building, and automotive industries use structural foam. Structural foam is desirable in many industrial applications due to, among other desirable attributes, high strength-to-weight ratios, good energy absorption properties, positive effects on thermal conductivity, and resistance to fire/flame. Most structural foam parts deal with bubble-like formations inside the structural foam part to get the foam effect. These bubble-like formations are generally manufactured by mixing a gas with a material such as a polymer. This process results in a cellular structure that contains mostly closed-cells. In addition, there is no regulated controlled structure to maximize strength with light weight and inexpensive production of complex shapes.
Many industries also use honeycomb structures. Honeycomb structures may be open-cell, and their structure can be regulated to some degree. However, maximizing strength with light weight and inexpensive production of complex shapes using honeycomb structures would be very difficult, time-consuming, and costly. Manufacturing processes used for honeycomb structures, such as the expansion process and the corrugation process, limit the effective and economical use of honeycomb structures in certain applications.
An advantage can be obtained using a rapid prototyping process, which could allow complex shapes to be made automatically from a solid computer-aided design (xe2x80x9cCADxe2x80x9d) model in the structural hollow form desired. A homogeneous structural foam part with varying density, available both as open or closed cell foams, could be produced. The internal structure would be like a honeycomb shape: semihollow and interconnected. Because of the ever-increasing use of structural foam throughout industry, manufacturers are continually searching for better and more economical ways of forming structural foam parts. Therefore, a need has arisen for a new method and system for constructing a structural foam part.
In accordance with the present invention, a method and system for constructing a structural foam part is provided that substantially eliminates or reduces disadvantages and problems associated with previously developed methods and systems.
A method for constructing a structural foam part is disclosed. The method comprises three steps. Step one calls for utilizing a rapid prototyping process to create a polymer mold. Step two requires filling the polymer mold with a material. The last step calls for heating the polymer mold and the material to heat set the material and to remove the polymer mold thereby forming the structural foam part.
A system for constructing a structural foam part is disclosed. The system comprises a computer operable to generate a solid CAD model having a corresponding CAD data format, and operable to translate the CAD data format into a CAM data format. A stereolithography process is operable to receive the CAM data format and create a polymer mold that corresponds to the shape of the solid CAD model. A material is used to fill the polymer mold, and a heat source that is coupled to the polymer mold and the material, removes the polymer mold by burning or melting away the polymer thereby leaving a formed structural foam part of heat set material.
Another method for constructing a structural foam part is also disclosed. The method comprises two steps. Step one calls for selecting a material, and step two requires utilizing a rapid prototyping process to create the structural foam part using the material.
An important technical advantage of the present invention is that the entire internal structure can be accessible from the outside. This allows for chemical coatings of the entire internal structure using, for example, electrolysis, electroless metal coating, or chemical vapor deposition (xe2x80x9cCVDxe2x80x9d) to change the chemistry of the internal surface for many new applications.
Another technical advantage of the present invention is that the accessibility of the internal structure would allow a medium such as water or air to circulate inside the entire structure. This could be used for plastic injection molds with an ideal cooling system automatically available in the molds, allowing for faster injection cycles, or as a heat exchanger in aerospace or automotive applications.
An additional technical advantage of the present invention is the effective and economical construction of complex shapes that result in homogeneous structural foam parts with varying density. In other words, structural foam parts can be optimally designed to have more strength in certain sections of the part, and less strength in other sections. These regulated controlled structures would maximize strength and minimize weight and cost. Structural foam parts can also be designed to optimize fluid flow for heating or cooling purposes. These complex parts could be used in a myriad of applications for the aerospace, aircraft, ship building, and automotive industries.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.